Efficient Low-temperature Ammonia Cracking Enabled by Strained Heterostructure Interfaces on Ru-free Catalyst

Area of Science:

• Materials Science
• Catalysis
• Energy Storage

Background:

• Ammonia (NH3) is a promising hydrogen (H2) carrier.
• Ruthenium (Ru) catalysts are costly for low-temperature NH3 cracking.
• Developing efficient, low-cost catalysts is crucial for H2 technology.

Purpose of the Study:

• To develop a cost-effective catalyst for low-temperature ammonia cracking.
• To investigate the performance and mechanisms of a strained heterostructure catalyst.
• To enhance hydrogen production rates for energy storage applications.

Main Methods:

• Synthesis of a strained heterostructure Co@BaAl2O4-x core@shell catalyst.
• Evaluation of catalytic performance at temperatures ranging from 475 to 575°C.
• Utilizing synchrotron X-ray absorption spectroscopy and diffraction to study catalyst structure under working conditions.
• Conducting kinetic studies to understand reaction mechanisms.

Main Results:

• The Co@BaAl2O4-x catalyst shows performance comparable to Ru-based catalysts at low temperatures.
• Achieved high conversion rates and a H2 production rate of 64.6 mmol H2 gcat-1 min-1.
• Identified enhanced NH3 adsorption and N─H dissociation due to tensile strained Co surface.
• Demonstrated efficient nitrogen desorption via strain release/restoration, preventing catalyst poisoning.

Conclusions:

• Lattice strain engineering and strong metal-support interfaces are effective strategies for catalyst design.
• The strained Co@BaAl2O4-x catalyst offers a viable alternative to Ru for low-temperature NH3 cracking.
• This work advances the development of efficient catalysts for hydrogen storage using ammonia.